The present invention is directed to the field of spherical bearings. More particularly this invention is directed to an improved spherical bearing which incorporates an elastomeric member to provide isolation of transmitted vibrations.
Spherical rod ends, that is, rod ends having spherical bearings, are widely used to make various connections including control cables and clutch linkages in class 8 trucks, farm tractors, off highway vehicles and other types of equipment. Such rod ends typically comprise a spherical bearing (a first metal element with an external spherical configuration and a second metal element with a complementary internal spherical surface with a Teflon.RTM. coating or a similarly configured plastic element) in a housing. The housing has i) a cylindrical opening that receives the spherical bearing and ii) a radially extending stud that typically has an internal thread that can be directly threaded onto the end of a cable, or the like. The first outer metal element can be retained in the housing by press fit or other mechanical connection such as staking, or the like. The second inner metallic element of the spherical bearing can be bolted to a bracket or other connector and the pivotability of the spherical bearing permits misalignment and movement of the cable relative to the connector, as needed.
A particular problem with such rod ends is that this rigid construction forms a linking path for the transmission of vibration, some of which takes the form of sound energy, i.e., noise. As efforts are made to make the cabs of these trucks, tractors and off-highway vehicles quieter, something must be done to isolate these transmission paths. The present invention proposes to bond an elastomeric layer to at least one of the inner and outer elements to interrupt (isolate) this direct transmission path. The elastomer may be natural rubber, neoprene, silicon elastomer, fluorocarbon elastomer, EPDM, SBR, PBR or blends thereof. Further, high temperature applications may require the use of other elastomers such as Viton.RTM. polymer, for example. In one embodiment, the elastomer is positioned between the inner and outer elements and bonded to both. In yet another embodiment, the spherical ring inner element is replaced with an elongated stud having a spherical head portion. The opposing end of the stud is externally threaded for bolting through a connector.
Various other features, advantages and characteristics of the present invention will become apparent after a reading of the following detailed description of the preferred embodiments.